Presentation on theme: "INTRODUCTION TO THE WORLD OF CARBON. TARGET AUDIENCE CLASS :IX AND X AGE GROUP :13 TO 15 YEARS."— Presentation transcript:

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LEARNING OBJECTIVES After interacting with this software, the learner will be able to :. Identify the allotropes of carbon Draw the structure of carbon atom. Distinguish the isotopes of carbon

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LEARNING OBJECTIVES explain how carbon dating is used for ascertaining the age of dead objects After interacting with this software, the learner will be able to :. State what is green house effect and take steps to control the pollution. State the causes of depletion of ozone layer

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Carbon is found in many different compounds. It is in the food you eat, the clothes you wear, the cosmetics you use and the gasoline that fuels your car. In addition, carbon is a very special element because it plays a dominant role in the chemistry of life. 1.It is in the food you eat. 2. The clothes you wear. 3. The cosmetics you use. 4.Gasoline that fuels your car. CARBON IS FOUND IN MANY COMPOUNDS : In addition, carbon is a very special element because it plays a dominant role in the chemistry of life.

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Atoms of the element carbon can link together in several different ways to form substances with very different properties. In diamond, the atoms form a three-dimensional network extending throughout the whole of a crystal. Because of this structure it is the hardest substance known. ALLOTROPES OF CARBON DIAMOND1.

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ALLOTROPES OF CARBON Graphite is made up of layers of carbon, consisting of hexagonal rings of atoms. The layers can slide over each other easily, so that graphite can even be used as a lubricant. 2. GRAPHITE

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ALLOTROPES OF CARBON FULLERENES In the family of substance fullerenes,the Buckminsterfullerene consists of 60 Carbon atoms forming a globe made up Of20 Hexagons and 12 pentagons. Atoms are linked to form spherical or Cylindrical surfaces 3.

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ISOTOPES OF CARBON C-12 C-13 C-14

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ISOTOPES OF CARBON C-12 Carbon has three naturally occurring isotopes: carbon-12 constitutes of all carbon atoms and serves as the standard for the atomic mass scale; It has 6 protons and 6 neutrons

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p n p p p n n n n P P n C-12 ATOM

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p n p p p n n n n P P n Next

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ISOTOPES OF CARBON C-13 carbon-13 is the only magnetic carbon isotope, which makes it very important for structural studies of compounds containing carbon It has 6 protons and 7 neutrons

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ISOTOPES OF CARBON C-14 Carbon-14 is produced by cosmic ray bombardment of nitrogen. It is radioactive with a half-life of 5,760 years. The amount of carbon- 14 remaining in historical artefacts can be used to estimate their age. It has 6 protons and 8 neutrons

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The number of protons an atom contains determines what that atom is. Since it now contains six protons, it's carbon. Carbon usually has six neutrons as well, in this form it's called carbon-12 (6+6=12). The unstable, eight-neutron version, however, is carbon-14 (6+8=14). C-12 Atom protons neutrons Nucleus of Carbon atom

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All radioactive atoms will eventually decay, or change, in some way. When a carbon-14 atom decays, one of its eight neutrons turns into a proton, emitting an electron (with a charge of -1) in the process. The atom is now stable. And with seven protons and seven neutrons, it is again nitrogen-14. See how C-14 changes to N- 14 atom Next Radioactive Carbon

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The carbon-14 created by cosmic radiation makes up only a fraction of the carbon in our atmosphere. But it is there, and just like carbon-12, it can be taken in by a growing plant and become a part of that plant. (As you may know, plants take in carbon dioxide, or CO 2, separate the carbon from the oxygen, then release the oxygen back into the atmosphere.) Radioactive Carbon Next

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. The percentage of carbon-14 in all of the living things is the same as the percentage of carbon- 14 in the atmosphere. At least it's the same while they're living. When a plant or animal dies, no carbon (in any form) can enter its system to become a part of it. Radioactive Carbon Next

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C-14 enters our body as we breathe Next

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The carbon-14 within every once-living thing will someday turn back into nitrogen-14. If we knew the amount of carbon-14 a once-living thing had while it was alive and the rate at which it changed (i.e., how fast it changed) back into nitrogen, then we could figure out how long ago it lived. Radiocarbon Dating NEXT